Hitherto, an apparatus which introduces ink to an actuator of a recording head and pressurizes and ejects ink by utilizing the bending of the actuator, such as a piezoelectric element or an electrostrictive element, according to an input signal or the local boiling of ink, which is caused by the actuator, such as a heating element, has been known as an image recording apparatus configured to record an image on a recording medium by ejecting ink according to an input signal.
For example, in an image recording apparatus referred to as a serial printer, the recording head is mounted on the carriage reciprocating in a direction perpendicular to a recording medium conveying direction. The serial printer records an image by reciprocating the carriage each time the recording medium is conveyed by a predetermined linefeed width. An electrically conductive flexible cable called a flat cable is connected to the carriage to control the recording head. The flat cable has a length sufficient to follow the reciprocating movement of the carriage without interfering therewith. The flat cable is disposed between the carriage and a main board and is bent substantially like a letter “U” (see, for example, JP-A-6-320835).
FIG. 23 shows a carriage 90 and a flat cable 91 of the conventional image recording apparatus. The carriage 90 reciprocates in a direction (a lateral direction, as viewed in FIG. 23) perpendicular to a conveying direction in which a sheet of recording paper is conveyed, while a recording head (not shown) mounted ejects ink to thereby form an image on the recording paper. The flat cable 91 is connected to the carriage 90 to transmit and receive electric signals to and from the main board. The flat cable 91 has an end portion 92 that is fixed to a frame (not shown) of the image recording apparatus and that is wired to the main board. Although not shown in FIG. 23, the carriage 90 is supported by guide members, such as a guide shaft and guide rails. A driving force is applied from a belt drive mechanism to the carriage 90.
As shown in FIG. 23, the flat cable 91 is led from the carriage 90 in a substantially horizontal direction and is bent substantially like a letter “U”. When the carriage 90 reciprocates, the flat cable 91 follows this movement of the carriage 90. Thus, the central position of the substantially U-shaped curved portion is shifted. When the carriage 90 moves rightward, as indicated by double-dash-chain lines in FIG. 23, the shape of the flat cable 91 is changed to increase the radius of the U-shaped curved portion. When the carriage 90 moves leftward, the shape of the flat cable 91 is changed to decrease the radius of the U-shaped curved portion.
Also, in each of image recording apparatuses of the type that ink is supplied to a recording head through an ink tube, the ink tube extends from a carriage 90 and is routed substantially like a letter “U” to follow the reciprocating movement of the carriage 90, similarly to the flat cable 91 (see JP-A-10-217496, JP-A-2003-11340, JP-A-2005-35033, JP-A-63-154354 and JP-A-2005-88524).